Estimates of primary production by ice algae and phytoplankton in the coastal ice-covered area near Syowa Station, Antarctica

Annual primary production of ice algae and phytoplankton under fast ice near Syowa Station (69°00'S, 39°35'E), Antarctica, was estimated. Mean daily production in each month from February 1983 to January 1984 was calculated with a mathematical model based on measured parameters of solar radiation, day length, attenuation coefficients of snow, ice and water, chlorophyll a standing stock, quantum yield for photosynthesis etc. Solar radiation measured at Syowa Station ranged from 0 E m-2 h-1 in June to 13.3 E m-2 h-1 in December. Relative light intensity estimated at the bottom of sea ice during the year ranged from 0 to 6.5% of incident solar radiation, due to attenuation with snow and ice. Maximum daily production of ice algae (34 mgC m-2 day-1) and phytoplankton (450 mgC m-2 day-1) was reached in December and in February, respectively. The estimated annual production of ice algae and phytoplankton was 3.5 and 17 gC m-2, respectively. These results indicate that summer phytoplankton production contributed remarkably to the primary production in the coastal ice-covered area near Syowa Station.